RE-COLONIZATION OF SOIL MICRO ARTHROPODS FROM 5CM DEPTH WITHIN 5 MONTHS PERIOD OF TREATMENT WITH ENDOSULFAN (ORGANOCHLORINE PESTICIDE) TREATMENT IN BENIN CITY, NIGERIA

Abstract

The re-colonization of soil arthropods was monitored for five months (April to August) 2007 to ascertain whether the application of Endosulfan (an organochlorine pesticide) in varying concentration levels would adversely affect the of sampling soil arthropod groups within a 0-5cm depth. Berlese Tullgren Extraction technique, extraction, sorting and identification were adopted and some soil physiochemical parameters (soil pH, temperature and moisture) were measured. Insects from eight different orders were consistently sampled and included members of Collembola, Coleoptera, Acarina and Isoptera. Others include Hymenoptera, Myriapoda, Crustaeca and Arachnida. There was a general initial decrease in the mean number of sampled soil arthropods in the treated plots from April to May but increased from June to August. Members of Collembola, Coleoptera and Acarina showed highest fauna abundance while species from Isoptera, Hymenoptera, Myriapoda, Crustaeca and Arachnida were least in abundance. Members of Acarina (mites) exhibited the highest re-colonization tendency while Crustacean species were least. The result revealed that, the mean number of sampled soil arthropods were significantly different (P<0.05) on the bases of pesticide concentration compared with the control. Except for soil pH and moisture content which showed positive correlation, soil temperature exhibited negative correlation with mean numbers of soil arthropod sampled. The implication of this survey is that, soil micro arthropod abundance in the farm is dependent among others on the concentration of pesticide applied and where application is not indiscriminate; soil micro arthropods have ability to re-colonize treated plots which could enhance high productivity from the farm in the long run.